Registry::build

protected Registry::build()

protected function build() {
  $cache = array();
  // First, preprocess the theme hooks advertised by modules. This will
  // serve as the basic registry. Since the list of enabled modules is the
  // same regardless of the theme used, this is cached in its own entry to
  // save building it for every theme.
  if ($cached = $this->cache->get('theme_registry:build:modules')) {
    $cache = $cached->data;
  }
  else {
    foreach ($this->moduleHandler->getImplementations('theme') as $module) {
      $this->processExtension($cache, $module, 'module', $module, $this->getPath($module));
    }
    // Only cache this registry if all modules are loaded.
    if ($this->moduleHandler->isLoaded()) {
      $this->cache->set("theme_registry:build:modules", $cache, Cache::PERMANENT, array('theme_registry'));
    }
  }

  // Process each base theme.
  // Ensure that we start with the root of the parents, so that both CSS files
  // and preprocess functions comes first.
  foreach (array_reverse($this->theme->getBaseThemes()) as $base) {
    // If the base theme uses a theme engine, process its hooks.
    $base_path = $base->getPath();
    if ($this->theme->getEngine()) {
      $this->processExtension($cache, $this->theme->getEngine(), 'base_theme_engine', $base->getName(), $base_path);
    }
    $this->processExtension($cache, $base->getName(), 'base_theme', $base->getName(), $base_path);
  }

  // And then the same thing, but for the theme.
  if ($this->theme->getEngine()) {
    $this->processExtension($cache, $this->theme->getEngine(), 'theme_engine', $this->theme->getName(), $this->theme->getPath());
  }

  // Hooks provided by the theme itself.
  $this->processExtension($cache, $this->theme->getName(), 'theme', $this->theme->getName(), $this->theme->getPath());

  // Discover and add all preprocess functions for theme hook suggestions.
  $this->postProcessExtension($cache, $this->theme);

  // Let modules and themes alter the registry.
  $this->moduleHandler->alter('theme_registry', $cache);
  $this->themeManager->alterForTheme($this->theme, 'theme_registry', $cache);

  // @todo Implement more reduction of the theme registry entry.
  // Optimize the registry to not have empty arrays for functions.
  foreach ($cache as $hook => $info) {
    if (empty($info['preprocess functions'])) {
      unset($cache[$hook]['preprocess functions']);
    }
  }
  $this->registry[$this->theme->getName()] = $cache;

  return $this->registry[$this->theme->getName()];
}